Large enclosed containers or trailers borne by a common mode of cargo movement tractor trucks, railroad flatcars, barges, and ships are familiar sites. A large portion of commercial goods are transported in such containers. The predominant cargo in these containers are goods packaged in cardboard cartons. By stacking the cardboard cartons on wooden pallets, the goods can be conveniently loaded into the rectangular, truckable containers. Often a forklift is used to move the heavy or bulky loads into and out of the container because the container is large enough to permit the entry of a loaded forklift. By such means, a manufacturer can load a container at the manufacturing plant or warehouse location and a warehouseman can unload palletized goods from the container at the destination of the goods without the need to unload the container. The container itself may pass through several intermediate transport companies and be borne by several different vehicles (e.g., barge, truck or train) before the goods themselves reach their final destination. For instance, the container may be first borne aboard a tractor trailer, then stacked on an inland waterway barge, then stacked in the hold of an oceangoing ship, later loaded on a railroad flat car, and finally loaded again on a tractor trailer for transport to a local warehouse or store. This is commonly known as containerized shipping.
The container itself offers weatherproof enclosure of the palletized, boxed goods, and case of intermediate handling by shippers. Containers offer relatively secure shipment of all types of goods, ranging from inexpensive perishables such as vegetables (in refrigerated trailers) to expensive, fragile electronic devices, such as computers.
As with any enterprise which involves the shipment and storage of valuable items to or through relatively unpopulated or unattended areas, thieves and vandals sometimes break into the closed containers. The containers themselves have rear doors for access which are built in accordance with a relatively common standard. The two large doors bisect one of the two smallest sides of the container to define the normally vertical doors exemplified in this disclosure. These doors normally open outward. Large rotating vertical rods are affixed to the doors and are used to latch and secure the doors in the closed position. One or more rods are affixed to each of the doors in aligned socket loops to permit rod rotation. The rods are mounted parallel to one another, near to the edges of the doors where the doors abut together and overlap when they are closed.
When the rods are rotated to a particular position, small flared latches on the upper and lower ends of the rods latch within and against open box like receptacles on the top and bottom frame edges of the container body so that the doors may be snugged down tight. Handles on the rods are rotated upward from their normal positions and move perpendicular to the rods. Hence when the doors are closed, an operator can rotate the rods to clasp the doors down tightly, lifting the handles near the end of the rotation and then drop the handles into latches on the door face so that they are again perpendicular to the rotating rods. This feature prevents the rods from rotating once the doors are snugged down tightly.
In the standard container door configuration, the rods themselves are not lockable by any built-in means or add-on device such as a common padlock. To prevent unauthorized entry, container shippers often buy "after-market" locks and hasps to secure the container doors. One common such device is an ordinary steel hasp which utilizes a padlock. Brammel, Inc. sells one such locking device. This device is in two halves, each affixed to one door and aligned so that, when the doors are closed, the two halves abut together and the loop portion of a padlock can be passed through holes drilled into the matching surfaces of the hasp. The disadvantage of such a device lies in the fact that the loop of the padlock is exposed and readily accessible to a thief or vandal possessing bolt cutters. By means of such common heavy duty bolt cutters, the loop of the padlock can be snipped and the padlock defeated.
One other common device is an adjustable lock consisting of two matched halves, one of which travels in grooves of the other half, allowing the width spanned by the lock to be adjusted. Brammel, Inc. also sells such a locking device. The halves of the device are approximately four inches wide. One of the halves has a rounded, ribbed longitudinal spine along its major axis which allows the loop of a padlock to fit between the protuberances of the spine to prevent movement of the two halves relative to one another once the padlock is in place. The outer ends of the locking device form a semi-circle so that they slip over and grip the parallel rods on the container doors. Hence by slipping the two halves of the device over the rods of the container door, bringing the two halves together by stabbing one of the halves into the grooves of the other half, and finally slipping a padlock over the longitudinal ribbed spine of one of the halves, the device becomes locked around the rods of the container door. Although this device is more difficult to defeat than the hasp device, the loop of the padlock is still relatively exposed and can be snipped by bolt cutters.